Windows 7 - EMERGENCY- Sony Vaio "Operating System Not Found" (friend's drive!)

My friend's hard drive in his Sony Vaio was riddled with viruses, malware, rootkits, you name it. I just had this hard drive in & out of my rig for the past couple days. I got it all set up fine, albeit with Win XP MCE, only installed my ethernet driver, and was all set to put it back in his laptop.

This happened once, & I figured it was a glitch, so I took it back out, into the rig, redid all I'd done, and took a system image of the drive. Now, I've put it back in the laptop, and AGAIN-- Vaio logo, then straight to black screen "Operating System Not Found." I promised him an absolutely no-cost no-risk wipe, (in exchange for him getting me a job) and now this!

Physically the drive is fine. It passed a disk check yesterday, and no clicking ever. The optical drive won't read my Dell OEM Win XP MCE disc, so I popped in my Win 7 disc to at least do a startup repair. It reports no operating systems installed, but is that just cuz there's no win 7 installed? I'm copying that system image over to my external to try that right now. Can I use the system image of XP with the 7 disc?

AND WHAT ELSE CAN I DO!

Your friend's computer came to you what OS installed?

From the factory, it had Vista, and belonged to his mom. Then she gave it to him, but had no discs or documentation saved from it. Someone before me had previously wiped that, and reinstalled Vista from some disc they had.

My 32bit Win 7 disc is able to be read. I wonder if I should do a preliminary install of that... My XP disc isn't showing up at all. I checked the Bios- not much there, but I set the 1st boot device as the CD-Rom & 2nd the internal hard drive. I just reseated it a third time, and the 20GB system image has copied from my rig to an external. Can I load an XP image through the Win 7 disc?

I don't care what I have to do. I have the system image so the system is saved.

When I put it back in my rig after the first time I saw "Operating System Not Found," there was a boot error so putting it back in the rig probably won't help. It'd be the same cycle.

If all else fails, you can get a set of recovery discs from Sony Support: Sony eSupport - Electronics

I don't have a Vista disc, or any Vista image, on me. What would their recovery discs allow me to do exactly?

They would recover the computer to its out-of-box state i.e. exactly how it was when it was bought new, which would mean anything not backed up would be lost and all applications would need to be reinstalled.

is the Certificate of Authenticity sticker still on the computer?

On laptops, the sticker is normally on the bottom and has a yellow color.

Yes, the COA is intact.

Okay, first, cuz speed is important, I'm going to take it down the street to this repair shop.

Once it's running something again, do you think I'd be able to, even painfully, reinstall XP and use the system image I have?

No.